Mesa 7i96S SSERIAL and pktuart

It's probably:

addf mesa_ifm.00 servo-thread

If in doubt about function names, run linuxcnc with a working
configuration with the desired components loaded and then
run this command (in a terminal):

halcmd show funct
 

Great! addf mesa_ifm.00 servo-thread was the solution! Now, HAL started and I have a data on RS485 Now, I am going to modify modbus driver to IFM bus - there are different opcodes and different checksum. It is the protocol of www.sabo.de I hope, this should not be so big problem.
But please, you have written about "known mesa-modbus bug" What are they? Will be better to know about them when there will be any problem with communication...
Thanx a lot for your help!

Thanx a lot again, it works finally! I have improved mesa-modbus to IFM bus and machine running

Glad that it worked for you.